The paper deals with the concept of 'egitimacy' of the political power. The author suggests that Max Weber cannot be considered a founder of the sociological discourse of legitimacy, as he only made use of a common category of legal studies. In fact, he rather tried to define distinct types of political authority then asked whether it is legitimate or not. The concept and the problem of legitimacy as conformity between values and political institutions is a descendant of a long philosophical debate on just government. Nevertheless, as a concept of the political sociology the term is not operational, as it refers to phenomena that belong to two incomparable domains: ambiguous and often indistinct values and actual political institutions. As a result, any solution of the problem of legitimacy is ambiguous and inherently political one. In fact, the question of legitimacy can only be asked when there is a political alternative, and in many cases it simply serves as an instrument to undermine the existent regime. In fact, the concept seems so popular exactly because it is an instrument that allows the scholar to manifest her own moral and political convictions.